Electrical system



March 27, 1951 SPENCER 2,546,952

ELECTRICAL SYSTEM Filed Feb. 27, 1946 P0155 SHHP/NG L/A/E r A? i A5 /J' 3 32 at 3 "i/iil/m Ll/Vf arr)? Patented Mar. 27, 1951 ELECTRICAL SYSTEM Percy L. Spencer, West Newton, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass, a corporation of Delaware Application February 27, 1946, SerialNo. 650,707

6 Claims.

This invention relates to an electrical system adapted to produce pulses of ultra-high frequency oscillations of relatively high energy con tent.

For certain purposes, for example, in pulse applications in radar equipment, an ultra-high frequency generator is energized intermittently to produce pulses of high frequency oscillations. Such a generator may consist of a magnetron having a plurality of cavity resonators which determine the frequency at which the magnetron oscillates. Such a device is energized by impressing thereon a substantially rectangular pulse of voltage. As such devices are designed to generate larger and larger amounts of power, difliculties are encountered in such pulsing operations. In the larger power devices, the excitation energy necessary to charge the capacitances and inductances of the cavity resonators becomes appreciable so that it is difiicult to supply the charging energy at the very beginning of the rectangular voltage impulse. In other words, at large power levels the oscillator appears to exhibit inertia eifects which interfere with the instantaneous starting of the oscillations as called for by the rectangular voltage impulse. Therefore, such high-power oscillators tend to exhibit undesirable spurious efiects due to the above inertia properties.

An object of this invention is to devise a highpower, ultra-high frequency oscillator which is capable of substantially instantaneous starting of oscillations in response to a substantially rectangular voltage impulse supplied thereto.

A further object is to accomplish the foregoing by a simple and reliable system.

The foregoing and other objects of this invention will be best understood from the following description of an exemplification thereof, reference being had to the accompanying drawing wherein:

Fig. 1 is a schematic diagram of an electrical system embodying the present invention; and

Fig. 2 is a diagram representing the relationship between the voltage impulses supplied to various parts of the system shown in Fig. 1.

In the system shown in Fig. 1, I represents an ultra-high frequency oscillator which may be of any suitable type. In the instance shown, this oscillator is of the magnetron type having an r anode 2 surrounding a cathode 3. The anode 2 is in the form of a cylinder, having inwardly projecting radial arms providing a plurality of anode faces coacting with the cathode 3 in a wellknown manner. The anode arms define a plurotates a discharging armature [6.

rality of cavity resonators which determine the frequency at which the magnetron oscillates. The oscillations generated by the magnetron may be led out therefrom by means of a coupling loop 5, one end of which is connected to the anode 2, and the other end of which extends out through a conducting pipe 6 and forming therewith a concentric line wave guide. The magnetron i is adapted to be supplied with power by having th anode and cathode connected to the opposite sides of the secondary winding 1 of a transformer 8, having a primary winding 9. The primary winding 9 is adapted to be supplied with pulses of current from any suitable source, which may be either alternating or direct, connected to a pair of terminals iii. A rectifier and blocking tube H, which may be of the thermionic type, has its anode connected to one of the terminals it, and its cathode connected by way of a choke i 2 to one side of a condenser I3. The opposite side of the condenser i3 is connected by Way of a pulse-shaping line M, the primary winding 9, and a conductor 15, to the other terminal 10. A spark gap It has one terminal thereof connected to the positive side of the condenser l3 at a point between said condenser and the choke l2, and its other terminal connected to the conductor 5. The spark gap it is of the type having a pair of sparking electrodes between which This discharging armature may be driven by a shaft I! from a suitable device such as a motor l8.

After the condenser it; has been charged through the rectifying and blocking tube II, the spark gap it fires and discharges said condenser through the pulse line it, the primary Winding and the conductor I5. As is well known, the pulse line 55 consists of a series of distributed capacitances and inductors which give a rectangular form to the pulse of current from the discharge of the condenser Hi. This pulse of current induces a corresponding rectangular voltage pulse in the secondary winding .1, which voltage pulse is thus impressed across the anode and cathode of the magnetron I. This voltage impulse may be that represented by B in Fig. 2.

As it has been pointed out above, in a case where the magnetron i is of the type which supplies oscillations of high energy content, the application of a substantially rectangular voltage B thereto would tend to produce undesirable effects. In order to eliminate these effects there is provided an additional or auxiliary magnetron [9. This magnetron is of the same type as magnetron l and consists of an anode 20 and a cathode 22.

The cavity resonators in the magnetron [9 are designated by the reference numeral 2!. Oscillations which are generated in the magnetron [9 may be led out therefrom by a coupling loop 23, one end of which is connected to the anode 20, and the other end of which is connected to a conductor 24, passing out through a conducting pipe 25, electrically connected both to the anode 2B and the anode 2. Here, likewise, the conductor 2t and the pipe form a concentric line wave guide. The conductor '24 is in turn connected to one end of a coupling loop 26 within the magnetron I, the opposite end of said coupling loop being likewise connected to the anode 2. In this way, oscillations which are generated within the magnetron is are coupled into the magnetron l.

The magnetron i9 is likewise supplied with power by having its cathode and anode connected to opposite sides of the secondary winding 2? of a transformer 28, having a primary winding 2%. The. primary winding is likewise adapted to be supplied with pulses of current from the terminal Hi. The cathode of the tube H isconnected by way of a choke it to one side of a condenser 31. The opposite side of the condenser is connected by way of a pulse-shaping line 32-, the primary winding 28 and a conductor 33 to the lower terminal it. A spark gap 34 similar to the spark gap It has one terminal thereof connected to the positive side of the condenser 3| at a point between said condenser and choke 38. The other terminal of the spark gap is connected to the conductor 33. The discharge armature 34 of the spark gap 34 is likewise driven from the shaft ll. However, the armature 34 is angularly displaced on the shaft ll with respect to the armature It sothat the spark gap 34 discharges the condenser 31 slightly in advance of the discharge of the condenser I3 by the armature it. As described above, the pulse-shaping line 32 causes a rectangular impulse of voltage to be supplied to the magnetron !9 through the intermediary of the transformer 28. Due to the angular relationship between the armatures of the two spark gaps, the voltage impulses supplied to the magnetron l9 lead and overlap the voltage impulses supplied to the magnetron l. One of these leading voltage impulses is indicated at A in Fig. 2.

When the impulse A is supplied to the magnetron It, said magnetron is of sufficiently low power so that the inertia eifects present in the magnetron I do not exist in the magnetron I9, or are so small as to be negligible. Therefore, the oscillations generated by the magnetron I!) are substantially coincident in duration with the impulse. A. The oscillations produced by the magnetron i!) are. fed into the magnetron I. They, however, are of such low energy content so as not to produce an appreciable output in the magnetron l as compared with the normal output thereof. Nevertheless, the oscillations generated by the magnetron H! are sufiicient to supply charging energy to the magnetron i, so that upon the application of the voltage impulse B- thereto, the magnetron I immediately starts to oscillate without the deleterious effects which heretofore have been encountered.

Of. course, it is to be understood that this invention is not limited to the particular details as described above as many equivalents will suggest themselves to those skilled in the art. Forexample, any convenient form of pulse line supplying a substantially rectangular voltage impulse may be utilized instead of the particular type of 4 pulse lines described above. Also, the oscillation generating tubes may be of any convenient type. It is accordingly desired that the appended claims be given a broad interpretation commensurate with the scope of the invention within the art.

What is claimed is:

1. In combination: a first circuit including a main electrical energy storage device and pulseshaping means coupled thereto; a first electrondischarge device coupled to said first circuit and adapted to be energized thereby to generate main electrical oscillations; a second circuit including an auxiliary electrical energy storage device and pulse-shaping means coupled thereto; a second electron-discharge device coupled to said second circuit and adapted to be energized thereby to generate auxiliary electrical oscillations; means for coupling the oscillations generated by said second electron-discharge device into said first electron-discharge device; means for charging said. energy storage devices; and means for discharging said energy storage devices to apply overlapping auxiliary and main pulses of voltage, respectively, to said second and first electrcn discharge devices.

2. In combination: a first circuit including a main electrical energy storage device and pulse shaping means coupled thereto; a first electrondischarge device coupled to said first circuit and adapted to be energized thereby to generate main electrical oscillations; a second circuit including an auxiliary electrical energy storage device and pulse-shaping means coupled thereto; a second electron-discharge device coupled to said second circuit and adapted tobe energized thereby to generate auxiliary electrical oscillations; means for coupling the oscillations generated by said second electron-discharge device into said first electron-discharge device; means for. charging said energy storage devices; a pair ofspaced electrodes, defining a spark gap connected across each of said first and second circuits; and means adapted to bridge said spark gaps to thereby discharge said energy storage devices and apply overlapping auxiliary and main pulses of voltage; respectively, to said second and said first electron-discharge devices.

3. In combination: a first circuit including a mainelectrical energy storage device and pulseshapingmeans coupled thereto; a first electrondischarge device coupled to said first circuit and adapted.- to be energized thereby to generate main electrical oscillations; at second circuit including an; auxiliary electrical energy storage device and pulse-shaping means coupled thereto; asecond electron-discharge device coupled to said second circuit and adapted to be energized thereby to generate mriliary electrical oscillations; means for coupling the oscillations generated by said second electron-discharge device into said firstelectron-discharge device; means forcharging said energy storage devices; a pair of spaced electrodes defining a spark gap connected. across each of said first and second circuits; and ganged, angularly displaced armatures adapted to bridge said spark gaps to thereby discharge said energy storage devices and apply overlapping auxiliary and main pulses of voltage, respectively, to said. second and said first electrondischarge devices.

4. In combination: a first circuit including a main electrical energy storage device and pulseshaping means coupled thereto; a first electrondis'charge device coupled to said first circuit and adapted to be energized thereby to generate main electrical oscillations; a second circuit including an auxiliary electrical energy storage device and pulse-shaping means coupled thereto connected in parallel with said first circuit; a second electron-discharge device coupled to said second circuit and adapted to be energized thereby to generate auxiliary electrical oscillations; means for coupling the oscillations generated by said second electron-discharge device into said first electron-discharge device; means for simultaneously charging said energy storage devices; and means for successively discharging said energy storage devices to apply overlapping auxiliary and main pulses of voltage, respectively, to said second and said first electron-discharge devices.

5. In combination: a first circuit including a main electrical energy storage device and pulseshaping means coupled thereto; a first electrondischarge device coupled to said first circuit and adapted to be energized thereby to generate main electrical oscillations; a second circuit including an auxiliary electrical energy storage device and pulse-shaping means coupled thereto connected in parallel with said first circuit; a second electron-discharge device coupled to said second circuit and adapted to be energized thereby to generate auxiliary electrical oscillations; means for coupling the oscillations generated by said second electron-discharge device into said first electron-discharge device; means for simultaneously charging said energy storage devices; a pair of spaced electrodes defining a spark gap connected across each of said first and second circuits; and means adapted to bridge said spark gaps to thereby discharge said energy storage devices successively and apply overlapping auxiliary and main pulses of voltage, respectively, to said second and said first electron-discharge devices.

6. In combination: a first circuit including a main electrical energy storage device and pulseshaping means coupled thereto; a first electrondischarge device coupled to said first circuit and adapted to be energized thereby to generate main electrical oscillations; a second circuit including an auxiliary electrical energy storage device and pulse-shaping means coupled thereto connected in parallel with said first circuit; a second electron-discharge device coupled to said second circuit and adapted to be energized thereby to generate auxiliary electrical oscillations; means for coupling the oscillations generated by said second electron-discharge device into said first electron-discharge device; means for simultaneously chargin said energy storage devices; a pair of spaced electrodes defining a spark gap connected across each of said first and second circuits; and ganged, angularly displaced armatures adapted to bridge said spark gaps to thereby discharge said energy storage devices successively and apply overlapping auxiliary and main pulses of voltage, respectively, to said second and said first electron-discharge devices.

PERCY L. SPENCER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

